Aluminium alloy for use in the building industry

ABSTRACT

A method of making from a rolled aluminium alloy sheet a product for outdoor use in the building industry, wherein the aluminium alloy has the following composition, in wt. %: Si 0.6 to 1.6, Mg 0.10 to 0.50, Mn 0.6 to 1.6, Cu 0.10 to 0.6, Fe 0.05 to 0.7, Ti 0.05 to 0.20, Zn up to 0.4, others and unavoidable impurities, each 0.05% max, total 0.25%, balance aluminium. Furthermore, the use of the sheet product for outdoor use in the building industry is disclosed.

FIELD OF THE INVENTION

The invention relates to a rolled Al—Si—Mg—Mn alloy sheet product. The sheet product is ideally used for outdoor use in the building industry, for example in the form of trapezoidal sheet.

BACKGROUND TO THE INVENTION

Some aluminium alloy sheet products in the art for use in the building industry include:

The AA4017 alloy registered with the Aluminium Association in 1995 and consisting of, in wt. %:

-   -   Si 0.6-1.6     -   Fe up to 0.7     -   Cu 0.10-0.50     -   Mn 0.6-1.2     -   Mg 0.10-0.50     -   Zn up to 0.20,     -   others and unavoidable impurities, each 0.05% max, total 0.15%,         remainder aluminium.

Each of European patent document EP-1484420-A1 and EP-1484421-A1 disclose an aluminium alloy product in the form of a sheet or extrusion having a composition of, in wt. %:

-   -   Si 1.2-2.2, preferably 1.4-2,     -   Fe <1.5, preferably <0.7,     -   Cu 0.2-0.8, preferably 0.3-0.5,     -   Mn 0.6-1.5, preferably 0.9-1.2,     -   Mg <0.20, preferably <0.15,     -   Zn <0.5     -   Ti <0.10,     -   remainder aluminium and unavoidable impurities.

DESCRIPTION OF THE INVENTION

As will be appreciated herein below, except as otherwise indicated, aluminium alloy designations and temper designations refer to the Aluminium Association designations in Aluminium Standards and Data and the Registration Records, as published by the Aluminium Association in 2014 and are well known to the person skilled in the art.

For any description of alloy compositions or preferred alloy compositions, all references to percentages are by weight percent unless otherwise indicated.

For this invention the term “sheet” or “sheet product” refers to a rolled product form in the gauge range of 0.2 to 3 mm in thickness at final gauge.

It is an object of the invention to provide a rolled Al—Si—Mg—Mn alloy sheet product for outdoor use in the building industry providing a balance of strength, corrosion resistance and good formability.

This and other objects and further advantages are met or exceeded by the present invention and providing a rolled aluminium alloy sheet product for outdoor use in the building industry, wherein the aluminium alloy has the following composition, in wt. %:

-   -   Si 0.6-1.6     -   Mg 0.10-0.50     -   Mn 0.6-1.6     -   Cu 0.10-0.6     -   Fe 0.05-0.7     -   Ti 0.05-0.20     -   Zn up to 0.4,     -   others and unavoidable impurities, each 0.05% max, total 0.25%,         balance aluminium.

The rolled aluminium alloy sheet product according to this invention provides a good balance in strength, improved corrosion resistance and good formability, in particular good roll formability. A further advantage of the rolled aluminium alloy sheet product is that it can absorb substantial amounts of Si-containing brazing sheet scrap material originating from the industrial scale production of brazing sheet material.

In an embodiment of the aluminium alloy the Mn-content is at least 0.70%, and preferably at least 0.75%. A preferred upper-limit for the Mn-content at most 1.4% and more preferably at most 1.20%.

In an embodiment of the aluminium alloy the Cu-content is at least 0.15%. The Cu-content is preferably at most 0.5%. In an embodiment the Cu-content is at most 0.4%, and preferably at most 0.35%.

In an embodiment of the aluminium alloy the Fe-content is at least 0.10%. The Fe-content is most 0.7%, and preferably is at most 0.45%.

Zn can be tolerated to substantial levels as an impurity element or can be added purposively. However, in an embodiment of the aluminium alloy the Zn-content is at most 0.25%, and preferably at most 0.20%. In a further embodiment the Zn-content is at most 0.10%, and more preferably at most 0.07%, such that the aluminium alloy is substantially free from Zn.

In an embodiment of the aluminium alloy the Mg-content is at least 0.20%, and preferably at least 0.25%, to increase the strength and formability of the sheet product. A preferred upper-limit for the Mg-content is 0.45%, and more preferably 0.40%.

In an embodiment of the aluminium alloy the Si-content is at least 0.90%, and preferably at least 1.10%, to increase the strength and formability of the sheet product. In a further embodiment the Si-content is at least 1.20%. A preferred upper-limit for the Si-content is 1.50%, and preferably 1.45%.

The Ti is purposively added to the aluminium alloy in a range of 0.05% to 0.20% to enhance the strength and the corrosion resistance, in particular the resistance against pitting corrosion is improved making the sheet product ideally suitable for outdoor use in amongst others the building industry. A preferred lower limit for the Ti-content is 0.07%, and more preferably 0.08%. A preferred upper limit for the Ti-content is 0.17%, preferably 0.15%, and more preferably 0.14%.

Zr is preferably not added to the aluminium alloy of the invention, but can be present as an unavoidable impurity element at a level of <0.05%, and preferably <0.03%, such that the aluminium alloy is substantially free from Zr.

Cr is preferably not added to the aluminium alloy of the invention, but can be present as an unavoidable impurity element at a level of <0.05%, and preferably <0.03%, such that the aluminium alloy is substantially free from Cr.

For the purpose of this invention the aluminium alloy sheet product is a bare sheet product, meaning that on either side it is devoid of any metallic layer(s) covering substantial parts of the sheet product. Such metallic layer(s) are commonly applied by roll bonding or casting techniques for in amongst others brazing sheet products in order to enhance the corrosion performance by providing sacrificial protection to the core alloy or to provide a filler metal, typically an AlSi alloy, for the brazing operation. Such metallic layer(s) have typically a thickness of 4% to up to 15% or more of the total product thickness should the aluminium alloy product have been clad on one or both sides.

The aluminium alloy sheet product can be provided however with a very thin conversion coating to enhance for example the adhesion of any applied organic coating layer, e.g. a paint layer or lacquer. The aluminium alloy sheet product can be provided with a textured surface structure via sheet metal embossing to provide an attractive surface appearance in the use for building applications such as façade and roof structures.

The aluminium alloy sheet product can be provided in an O-temper or an H-temper, in particular a temper selected from the group of H12, H14, H16, H18, H22, H26 temper.

In a further aspect of the invention it relates to the use, or to a method of use, of the rolled aluminium alloy sheet product according to this invention for outdoor use in the building industry, signposting or decoration. Preferred examples for use in the building industry are façade structures or façade panels, garage doors and metal standing seam roofs. Such applications typically comprise folded or roll formed structures, which may take benefit from the good formability and corrosion resistance of the sheet product in accordance with this invention. A preferred embodiment of the sheet product concerns its use as trapezoidal sheet. 

1. A method of making from a rolled aluminium alloy sheet a product for outdoor use in the building industry, signposting, or decoration, comprising: folding or roll forming the aluminium alloy sheet into the product, wherein the aluminium alloy has the following composition, in wt. %: Si 0.6-1.6 Mg 0.20-0.50 Mn 0.6-1.6 Cu 0.10-0.6 Fe 0.05-0.7 Ti 0.05-0.20 Zn up to 0.4, others and unavoidable impurities, each 0.05% max, total 0.25%, balance aluminium.
 2. The method according to claim 1, wherein the rolled aluminium alloy has a Mn content is at least 0.70%.
 3. The method according to claim 1, wherein the rolled aluminium alloy has a Mn content of at most 1.4%.
 4. The method according to claim 1, wherein the rolled aluminium alloy has a Cu-content of at least 0.15%.
 5. The method according to claim 1, wherein the rolled aluminium alloy has a Zn-content of at most 0.10%.
 6. The method according to claim 1, wherein the rolled aluminium alloy has a Ti-content of at least 0.07%.
 7. The method according to claim 1, wherein the rolled aluminium alloy has a Ti content of at most 0.17%.
 8. The method according to claim 1, wherein the rolled aluminium alloy has a Mg-content of at least 0.25%.
 9. The method according to claim 1, wherein the rolled aluminium alloy has a Si-content of at least 0.90%.
 10. A method according to claim 1, wherein the rolled aluminium alloy sheet is devoid of any metallic layers covering substantial parts of said rolled aluminium alloy sheet.
 11. The method according to claim 1, wherein the rolled aluminium alloy sheet is provided with an organic coating.
 12. The method according to claim 1, wherein the rolled aluminium alloy sheet is provided with a surface structure via sheet metal embossing.
 13. The method according to claim 1, wherein the rolled aluminium alloy sheet is in the form of trapezoidal sheet.
 14. The method according to claim 1, wherein the product is for outdoor use in the building industry.
 15. The method according to claim 1, wherein the rolled aluminium alloy sheet is part of a façade structure or roof structure.
 16. The method according to claim 1, wherein the rolled aluminium alloy sheet has a gauge in the range of 0.2 to 3 mm.
 17. The method according to claim 1, wherein the rolled aluminium alloy sheet has a Ti-content of at least 0.08%.
 18. The method according to claim 1, wherein the rolled aluminium alloy sheet has a Ti-content of at most 0.15%.
 19. The method according to claim 1, wherein the rolled aluminium alloy sheet has a Mn-content of at least 0.75%.
 20. The method according to claim 1, wherein the rolled aluminium alloy sheet has a Mn-content of at most 1.2%.
 21. The method according to claim 1, wherein the rolled aluminium alloy sheet has a Cu-content of at most 0.5%.
 22. The method according to claim 1, wherein the rolled aluminium alloy sheet has a Cu-content of at most 0.4%.
 23. The method according to claim 1, wherein the rolled aluminium alloy sheet has a Si-content of at most 1.50%.
 24. The method according to claim 1, wherein the rolled aluminium alloy sheet has a Si-content of at most 1.45%.
 25. The method according to claim 1, wherein the rolled aluminium alloy sheet has a Fe-content of at most 0.45%. 